What is the concept of Array.map?

Question

I am having problems understanding the concept of Array.map. I did go to Mozilla and Tutorials Point, but they provided very limited info regarding this.

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Answer 1

Javascript map() Syntax

arrayObj.map(callback[,context]);

arrayObj is a original array on which map() is invoked.

The map() takes 2 named arguments, First is a callback function and the second is a context object. callback function gets triggered on every element of an array.

In addition, callback function takes 3 arguments:

function callback(currentElement,index,array){

}

currentElement – This is a current elements of array which is passed to callback function

index – Index of the current element

array – complete array on which map() is applied

Out of these 3 elements, currentElement parameter is mandatory while the rest 2 parameters are optional.

However, map() does not change the original array, it creates a new array element which is generated by callback function.

You can read more on JavaScript map function